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Marine Ecology Progress Series

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MEPS 703:17-30 (2023)  -  DOI:

Chemical and biological vertical distributions within central Arctic (>82°N) sea ice during late summer

A. Torstensson1,2,4,*, G. M. Showalter1, A. R. Margolin3, E. H. Shadwick3,5, J. W. Deming1, W. O. Smith Jr.3,6

1School of Oceanography, University of Washington, Seattle, WA 98195, USA
2Department of Ecology and Genetics, Limnology, Uppsala University, 752 36 Uppsala, Sweden
3Virginia Institute of Marine Science, College of William & Mary, Gloucester Pt., VA 23602, USA
4Present address: Swedish Meteorological and Hydrological Institute, 426 71 Västra Frölunda, Sweden
5Present address: CSIRO Oceans & Atmosphere, Hobart, Tasmania 7001, Australia
6Present address: School of Oceanography, Shanghai Jiao Tong University, Shanghai 200240, PR China
*Corresponding author:

ABSTRACT: We assessed the distribution of biota (autotrophs and heterotrophs) and associated carbonate chemistry variables in Arctic sea ice at latitudes >82°N during late summer and early autumn 2018. The sampled sea ice was relatively thick (average 1.4 m) with variable snow cover (mean 7 cm) and low bulk salinities throughout. Most measured variables, including carbonate chemistry parameters, were low in the upper half of the ice cores, but increased with depth. Measurements of particulate organic carbon (POC), chlorophyll a (chl a), bacterial abundance, and particulate extracellular polysaccharide (pEPS) in the cores strongly suggested that detrital carbon was the major particulate organic pool. Near the ice-water interface, autotrophic material comprised ca. 50% of the total POC, whereas pEPS and bacterial carbon accounted for ca. 8 and 1% of the total POC, respectively. Under-ice water was nutrient poor, providing only a small input of nutrients to support autotrophic growth, at least during the time of our sampling. While the Arctic Ocean has substantial interannual variability in sea-ice concentration and thickness, these measurements enrich the available database and suggest that during years when autumn sea ice is >1 m thick, sea-ice biota are limited in activity and biomass.

KEY WORDS: Algae · Bacteria · Sea ice microbial community · Carbon · Biomass · EPS · DIC · pH

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Cite this article as: Torstensson A, Showalter GM, Margolin AR, Shadwick EH, Deming JW, Smith WO Jr (2023) Chemical and biological vertical distributions within central Arctic (>82°N) sea ice during late summer. Mar Ecol Prog Ser 703:17-30.

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